Consolidated Statements of Comprehensive Income (Loss) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net income	$ 76.0	$ 81.2	$ 207.0	$ 210.7
Other comprehensive income (loss):
Defined benefit pension and other postretirement plans, net of income taxes	(13.0)	(114.5)	(40.3)	(79.5)
Currency translation adjustments	14.5	(7.6)	5.1	(6.3)
Gain (loss) from hedging activities, net of income taxes	1.5	(1.7)	3.0	(1.2)
Total other comprehensive income (loss) attributable to noncontrolling interests	(0.3)	(0.2)		0.2
Total other comprehensive income (loss)	2.7	(124.0)	(32.2)	(86.8)
Comprehensive income (loss)	78.7	(42.8)	174.8	123.9
Less: comprehensive (income) loss attributable to noncontrolling interests	(0.2)	0.3	(1.3)	0.4
Comprehensive income (loss) attributable to W. R. Grace & Co. shareholders	$ 78.5	$ (42.5)	$ 173.5	$ 124.3